fix apt default_release attribute broken in 12.0

the apt provider attempts to check if it has a provider that
responds to :default_release (i.e. a real apt_package resource) via
if the provider attribute is explicitly set or not, which is relying
on a side-effect which broke in 12.0.  the correct behavior is just
to duck-type the new_resource object and see if it
respond_to?(:default_release) and then use it if it does.

Also the unit tests were not testing the apt_provider against both the
package and apt_package resources.  Added some hacky spec code (which
needs a cleanup) to at least exercise the use cases.

1 files changed, 3 insertions, 5 deletions

diff --git a/spec/unit/resource/apt_package_spec.rb b/spec/unit/resource/apt_package_spec.rb
index be8eb9c324..3c31f63dd7 100644
--- a/spec/unit/resource/apt_package_spec.rb
+++ b/spec/unit/resource/apt_package_spec.rb
@@ -29,12 +29,10 @@ describe Chef::Resource::AptPackage, "initialize" do
     os: "linux",
   )
 
-  before(:each) do
-    @resource = Chef::Resource::AptPackage.new("foo")
-  end
+  let(:resource) { Chef::Resource::AptPackage.new("foo") }
 
   it "should support default_release" do
-    @resource.default_release("lenny-backports")
-    expect(@resource.default_release).to eql("lenny-backports")
+    resource.default_release("lenny-backports")
+    expect(resource.default_release).to eql("lenny-backports")
   end
 end